Prime-Boost Immunization with Adenoviral Vaccines

Robert A. Seder, M.D. April 18th, 2012

Dale and Betty Bumpers

Vaccine Research Center National Institute of Allergy and Infectious Diseases National Institutes of Health

Immune Requirements for Vaccines: HIV, Malaria and Tuberculosis

• HIV, Malaria and TB vaccination will require generation of antibody and/or T cell responses: • Phase III efficacy trials for HIV and Malaria have shown ~30%

protection correlating with antibody • CD8+ T cells will improve HIV viral control or malaria in the liver

• CD8+ T cells can be induced by:

• Protein/DC Targeted Vaccines: • Requires cross-presentation-low magnitude

• DNA Vaccines: Require multiple immunizations • Viral Vaccine Vectors:

• Most efficient method of inducing robust T cell immunity

Priming: How do novel chAds compare to human rAds for

induction of protective CD8 T cell responses?

Question

Experimental Outline

Day 0 Vaccinate

Group: Vaccine:

1 rAd5:SIV-Gag

2 rAd28:SIV-Gag

3 rAd35:SIV-Gag

6 chAd3:SIV-Gag

7 chAd63:SIV-Gag

8 PBS

Days 14, 21, 28, 35 and 70 Peripheral blood- CD8+ SIV Gag Tetramer time course

• Administered each vector : •1 x 109 PU

•1 x 108 PU

•1 x 107 PU

• Vaccinated SQ in footpad

Day 90-100 Infectious challenge

Dose Titration of Vectors Correlates With Hierarchy Observed in Clinical Studies

SIV-Gag specific CD8+

T cells (%)

Days after vaccination

rAd5 rAd28 rAd35

chAd63 chAd3

1 x 109 PU 1 x 108 PU 1 x 107 PU PBS

Key to dose:

0 25 50 750

5

10

15

20

25

30

0 25 50 750

5

10

15

20

25

30

A Predictive Hierarchy for CD8+ T Cell Immunity Is Observed at 1 x 107 PU Dose

SIV-Gag specific CD8+ T cells (%)

0 25 50 750

5

10

15

20

25

30

rAd5 rAd28 rAd35 PBS

Key to vectors: rAd5 chAd3 chAd63 PBS

Key to vectors:

0 25 50 750

5

10

15

20

25

30

0 25 50 750

5

10

15

20

25

30

0 25 50 750

5

10

15

20

25

30

SIV Gag specific CD4+ T cell responses were low and comparable for all Ads

TNF+ IL-2+ TNF+ IL-2+

IFN-g+ TNF+ IL-2+

IFN-g+

Differentiation Terminal effector

Naïve cell

IFN-g+ TNF+

IFN-g+ IL-2+

CD8

IFN-g

TNF

CD4

T Cell Quality

Darrah et al, Nat Med, 2007: Using Leishmania major infection model: • Protective vaccines induced CD4 Th1 cells

that co-expressed IFN-g, IL-2 and TNF • CD4 Th1 cells that co-expressed 3

cytokines had higher MFI

3 cytokines 2 cytokines 1 cytokine Key to IFN-g, IL-2 and TNF co-expression:

Betts et al, Blood, 2006: Using HIV long-term non-progressors: • Lower long-term viral load has more multi-

functional cells • Includes MIP1b, CD107a (degranulation)

In spleen at day 70 post-vaccination:

G+ 2+ T+ G+ 2+ T- G+ 2- T+ G+ 2- T- G- 2+ T+ G- 2+ T- G- 2- T+ Key:

rAd5:

1 x 109 PU 1 x 108 PU 1 x 107 PU

Quality of Ad5 CD8+ T Cells

CFUs in spleen (log10)

1 x 10e9 PU 1 x 10e8 PU Key: 1 x 10e7 PU

rAd5 rAd28 rAd35 PBS chAd63 chAd3 PBS rAd5

Protection Against Listeria-SIV Correlates With CD8 Response Magnitude

0 5 10 153

4

5

6

7

hAd5 Control

aCD4 aCD8

+ - - - - - - -

+ + - -

+ - + -

+ - - +

+ - + +

% SIV Gag CD8 T cells

CFUs in spleen (log10)

0 5 10 153

4

5

6

7 y = -0.1647x + 5.4151 R² = 0.27259 P < 0.0001

• Chimp-derived Ad vectors potently induce Gag- specific CD8+ T cell responses • Have a broad range of effective dose compared to low

sero-prevalent human-derived vectors • chAd3 protects against Listeria challenge at all doses

and against Ebola in NHP

•Dose titration highlights hierarchy in magnitude and protective capacity responses between the vectors at the lowest dose:

Summary

rAd5 rAd35 ≈ chAd3 > chAd63 = rAd28 > >>

• What is the mechanistic basis for the hierarchy in CD8 immunity? • How do these vectors differ in:

• Amount or duration of antigen expression? • Innate immunity?

Question

Prime-Boost Immunization for HIV Vaccines

• HIV Phase III Trials

– ALVAC (Env/Gag)-Env Protein/Alum (RV-144)-~30% Protection

– DNA (Env/Gag)-Ad5 (Env/Gag) (HVTN 505)-Ongoing

Ongoing and Future Clinical Studies

– DNA-Pox (MVA, NYVAC)

– Ad26-MVA

Question: What is optimal Prime-Boost Regimen for inducing robust HIV Env and Gag immunity

Prime-Boost Immunization for HIV Vaccines

• Prime

– Compare DNA vs rAd priming- Does the magnitude of the primed CD8+ T cell response correlate with improved immunity after boosting?

• Boost

– Compare potency of Pox versus Ad viral boost for CD4 and CD8+ T cell responses

0 10 20 30 40 50 60 700

10

20

30

40

50

rAd28 / -

- / rAd5

- / chAd3

- / -0 10 20 30 40 50 60 70

0

10

20

30

40

50

rAd28 / rAd5

rAd28 / chAd3

rAd28 / -

- / rAd5

- / chAd3

- / -0 10 20 30 40 50 60 70

0

10

20

30

40

50

rAd28 / -

- / -0 10 20 30 40 50 60 70

0

10

20

30

40

50

0 10 20 30 40 50 60 700

5

10

15

20

25

30

35

0 10 20 30 40 50 60 700

5

10

15

20

25

30

35

DNA / -

- / rAd5

- / chAd3

- / -0 10 20 30 40 50 60 70

0

5

10

15

20

25

30

35

DNA / rAd5

DNA / chAd3

DNA / -

- / rAd5

- / chAd3

- / -

rAd5 and chAd3 Strongly Boost DNA or Ad28 Primed CD8+ T Cell Responses

0 10 20 30 40 50 60 700

5

10

15

20

25

30

35

DNA / -

- / -

Key to Prime / Boost:

Key to Prime / Boost:

Days after boost

% of CD3+CD8+ T cells that are

Tetramer+

NYVAC Boosts Ad-Primed CD8 T cell Responses More Robustly than Heterologous chAd3

Days after boost

Key to Prime / Boost:

Key to Prime / Boost:

% of CD3+CD8+ T cells that are

Tetramer+

0 10 20 30 40 50 60 700

5

10

15

20

25

30

35

chAd3 boosted

0 10 20 30 40 50 60 700

10

20

30

40

50

60

70

NYVAC boosted

0 10 20 30 40 50 60 700

5

10

15

20

25

30

35

PBS

0 10 20 30 40 50 60 700

5

10

15

20

25

30

35

chAd3

PBS

0 10 20 30 40 50 60 700

5

10

15

20

25

30

35

rAd5

rAd28

rAd35

chAd3

PBS

0 10 20 30 40 50 60 700

10

20

30

40

50

60

70

rAd5

rAd28

rAd35

chAd3

PBS

0 10 20 30 40 50 60 700

10

20

30

40

50

60

70

rAd5

rAd28

rAd35

chAd3

PBS

0 10 20 30 40 50 60 700

10

20

30

40

50

60

70

rAd35

PBS

0 10 20 30 40 50 60 700

10

20

30

40

50

60

70

PBS

Prime-Boost Immunization with Ad and Pox Induce Potent HIV Env Specific CD4+ T Cell Responses

rAd 5

rAd 28

rAd 35

chAd 3

MVA chAd 3 Ctl

MVA Boost

chAd 63

rAd 5

rAd 28

rAd 35

chAd 3

MVA chAd 3 Ctl

Priming

chAd 63

HIV Env CD4+/IFN-g

Responses (%)

Time of Boost Peak Post Boost

Quality of a Primed-Boosted CD4+ T Cell Response

rAd5 rAd28 rAd35 MVA

Time of MVA boost

Peak post MVA boost

rAd5 rAd28 rAd35 MVA

Ad prime at 1 x 108 PU:

G+ 2+ T+ G+ 2+ T- G+ 2- T+ G+ 2- T- G- 2+ T+ G- 2+ T- G- 2- T+

Key to pies:

Key to arc: IFNγ production

Prime-Boost Immunization with Ad and Pox Induce Potent HIV Env Specific CD8+ T Cell Responses

rAd 5

rAd 28

rAd 35

chAd 3

MVA chAd 3 Ctl

MVA Boost

chAd 63

rAd 5

rAd 28

rAd 35

chAd 3

MVA chAd 3 Ctl

Priming

chAd 63

HIV Env CD8+/IFN-g

Responses (%)

Time of Boost Peak Post Boost

Quality of a Primed-Boosted CD8+ T Cell Response

rAd5 rAd28 rAd35 MVA

Time of MVA boost

Peak post MVA boost

rAd5 rAd28 rAd35 MVA

Ad prime at 1 x 108 PU:

G+ 2+ T+ G+ 2+ T- G+ 2- T+ G+ 2- T- G- 2+ T+ G- 2+ T- G- 2- T+

Key to pies:

Key to arc: IFNγ production

• Priming:

•Ad 28, ChAd 3, ChAd 63 efficiently prime T cells •Ad35 is limited for priming CD4 and CD8 T cell immunity •Pox viral vectors are limited for priming CD8+ T cells

• Boosting:

• Pox viral vectors potently boost CD4, CD8 and Ab responses and are true heterologous boost following Ad priming • Multiple Ad vectors boost T cell responses

•Maintenance:

•For CD4+ T cells and antibody- pox or protein/adjuvant vaccines can be used •For CD8+ T cells will need Ad or Pox

Summary: Lessons Learned